Controlling means for electric motors.



. G. PECK.

CONTROLLING MEANS FOR ELECTRIC MOTORS.

APPLICATION FILED SEPT.25| 1916.

Patented Feb. 4, 1919.

2 SHEETSSHEET I.

F. G. PECK.

comomwe MEANS FOR ELECTRIC MOTORS.

APPLICATION FILED SEPT-25.1916- Lg93 53g Patented Feb. 4, 1919.

2 SHEETSSHEET 2.

FREDERICK c. PECK, or PHILADELPHIA,

PENNSYLVANIA, ASSIGNOR OF ONE-HALF TO JAMES B. WILSON, OF PHILADELPHIA,PENNSYLVANIA.

' CONTRPLLING MEANS FOR ELECTRIC MOTORS.

Specification of Letters Patent.

Patented Feb. 4, 1919.

Application filed September 25, 1916. Serial No. 121,938.

To all whom it may concern:

Be it known that I, FREDERICK G. Peon, a subject of the King of GreatBritain, residing at Philadelphia, in the county of Philadelphia and,State of Pennsylvania,

have invented a new and useful Improvement in Controlling Means forElectric Motors, of which the following is a specification.

This invention relates to controlling means for electric motors, andmore particularly to means for changing the field I tion shown,

circuit of a motor so as to increase or decrease the field strength.

The objects of the invention are to produce controlling means of thiskindof im proved construction in which the field current of a motor iscontrolled by means of a snap switch actuated by a part of thecontroller; also to provide a snap* switch of improved-constructionwhich is particularly ada ted to housed in connection with a control oror the like for controlling the motor fieldcurrent. a

In the accompanying drawings: Figure '1 shows diagrammatically a motorcontroller and the circuits controlled ing the thereby, and a snapswitch embod ation U0 invention arranged in operative the controller. I

. Fig. 2 is a detached View of the movable member of the motorcontroller.

Fig; 3 is a side elevat'on of the snap switch detached from thecontroller.

Fig. 4: is a top plan view thereof.

Fig. 5 is a sectional elevation on line 55, Fig. 4, showing the parts ofthe switch in different positions.

Fig. 6 is a detached perspective view of the actuating member of theswitch.

Fig. 7 is a sectional end elevation on line 7-7, Fig. 4.

The motor controller as shown diagrammatically in Fig. 1 includes acontact strip A which is ada a contact strip a or any one of a pluralityof contacts or short strips a, a contact strip A, which is adapted to beconnected with any one of a plurality of contacts or short strips a orwith a contact stripe, and a contact member B which, in the construcisadapted to be moved lengthwise of the contact strips for connectingthestrips A A with the contacts a a and a a respectively. a representsinsulated d to be connected-with plates or segments with which themovable contact member may be placed into engagement for interruptingthe supply of current to the motor.

The movable contact member B, as shown, consists of a handle portion 6on which are mounted two connectors or bridge members 6 btinsulated fromthe handle I). The connector b is adapted to connect the contact strip Awith the strip or piece a or with the contacts a and the connector 6' isadapted to connect the contact strip A with the contacts a and thecontact strip a. All of these parts may be of any usual or suitableconstruction and of themselves constitute no part of this invention.

The contact strip A is connected by means of a conductor 0 with anysuitable source of power, such, for example, as a storage battery C, andthe contact strip a is connected by means of a conductor 0 to thearmature D of the motor. The contacts a are connected by means ofconductors c to a suitable armature resistanced which is connected bymeans of a conductor (1 to the contact strip a. Consequently as theconnector bof the movable contact member movesfrom left to right in Fig.1, the full armature resistance 03 is first placed in serice with thecircuit connecting the motor armature with the source of power, and asthe movable member of the controller moves to the right this resistanceis gradually decreased until the connector 6 connects the contact stripsA. (1*, which short circuits the armature resistance. The other terminalof the armature is connected by means of conductors d and c to thesource of power C.

The contacts a are connected by means of conductors c with a group ofresistance units E, and the contact plate or strip a is connected bymeans of a conductor 6 with one of the contacts a", through whichcurrent passes. from the battery when the contacts a or the contactstrip a are con nected with the contact strip A by means contact stripA, so that no resistance is inserted into the field circuit. When themovable contact member connects the first of the contacts a with thecontact strip A,

a small resistance is into the field c1rcu1t, which reslstance islncreased as the movable conta-ct'member is moved to the right. Anyother connections or circuits between the parts of the controller andthe motor, battery and resistance devices may be employed.

In order to obtain a still greater variation in the speed of the motor,means are provided for connecting the coils of the field circuit eitherin series or in parallel.

In changing from the series connection to the parallel connection, orvice versa, while the armature is connected with the source of currentsupply, it is desirable that this change should be instantaneous so thatthe field circuit is not interrupted for any appreciable length of timewhile current is flowing through the armature. In order to accomplishthis result a snap switch is provided which is actuated by the movablemember of the controller in such a manner that the field coils of themotor will be connected in parallel when the motor is tact g suitablyinsulated from the switch.

member, and at its other end with two contacts g 9 which also aremounted on and insulated from the movable switch member G. The movablecontact -g' is adapted to enga e with a fixed contact f mounted on andinsulated from the base F when the movable switch member is in theposition shown in Fig. 3 and in fulllines in Fig. 5, and the movablecontacts g g are adapted to engage with fixed contacts f f alsomounted'on and insulated from the base F when the switch member isin-the position shown in dotted lines in Fig. 5. The contacts g g and 8are preferably mounted on strips g of. spring metal or resilientmaterial which are secured on the movable switch member and whichyieldingly press the contacts of the movable switch member intoengagement with the fixed contacts of thebase of the switch. I

In order to move the switch member G rapidly from one positiontoanother, a switch actuating member H is preferably provided which, inthe construction shown,

comprises an intermediate or. body portion it having upwardly extendingarms 7:. h which are pivoted at their upper ends at g on the posts f ofthe base of the switch, and downwardly extending arms hf 71. whichextend through a slot hin the base into a position to be engaged by apart of the movable member of thecontroller, the ends of the slotlimiting the movement of the switch actuating member. The switchactuating member H is connected with the movable switch member by meansof a coil spring I secured at its lower end to a lugz' on the atingmember from one position to the other,

the movable member B of the controller is provided with an'extension orlug i which is adapted to engage the arm 72. when the movable member ismoved to the right in.

Fig. 1 to throw the switch into position to connect the motor fields inseries, and to engage the arm 71. when moved to the left in Fig. ,1 tothrow the. switch into the other position in which the motor fields areconnected in parallel;

The connections between the terminals of the field controlling switchand the motor fields are preferably made as follows:

In the motor which is shown diagrammatically in Fig. 1, the field coilsare divided into two sets, groups or coils K K which may be eitherconnected. in series or in parallel by means of the field controllingswitch. One terminal of the coil K is connected by means of a conductoris with the fixed contact f and the other terminal of this coil isconnected by means of a conductor k to the fixed contact f. Theterminals of the other coil K are connected by means of conductors k krespectively with the contacts 9 of the movable switch member G; Theconductor is is connected by means of a conductor 70* to the fixedcontact f of the switch and the movable contact g is connected by meansof a conductor k to the conductor k Consequently when the switch is'inthe position indicated in Fig. 1, the two coils or groups of coils K Kof the motor field are in series, and

when the switch is in the other position the Other two coils areconnectedin parallel. connections between the motor fields and theswitch may be used if desired.

By means of the apparatus described a cdnsiderable variation in speed ofthe motor can be obtained, since the motor when starting with themovable member of the controller in the first position has the coils orgroup of coils of the field circuit-connected in parallel and aresistance is inserted in the armature circuit. controller handle hasbeen moved to the right in Fig; .1, the fields are in series and theentire field resistance is in the field circuit, so that the motor runsat its maximum speed. In intermediate positions the speed of the motorcan be regulated as desired. The apparatus is simple to operate sincethe coils are automatically placed into either the series or parallelposition by means of the movable part of the controller, so that noadjustment or manipulation other than the movement of the controlleritself is required. The apparatus is particularly desirable for use inconnection with electric motor vehiclessince it makes it possible to usea shunt motor, owing to the fact that by placing the motor fields inparallel a heavy starting torque may be produced. The apparatus may,however, be used for other purposes. The field changing switch is shownin the construction illustrated as applied, to a shunt motor, but itwill be understood that it is not intended to limit the use of thisswitch to shunt wound motors since the switch could perform the samefunction on series or compound wound motors.

I claim as my invention:

1. The combination with a source of electric power and a shunt-wounddirect current electric motor havin a field winding consisting of aplurality ot coils, of a controller for supplying a gradually decreasingflow of current to the motor field, and a switch by means of which saidfields are connected in parallel when the motor is starting and which isactuated by the controller before the current in the motor fields hasreached its minimum strength. for connecting said fields in series.

2. The combination with a source of electric power and a shunt wounddirect current electric motor having a field winding consisting of aplurality of coils, of a controller for regulating the flow of currentto the motor field a switch separate from said controller and by meansof which said field coils are connected in parallel when the motor isbeing started, and a part on said controller adapted to actuate theswitch for connecting the coils of the motor field in series before thecurrent in the motor fields has reached its minimum strength.

3. The combination with a source of elec tric power and an electricmotor having a field winding consisting of a plurality of coils, of acontroller for regulating the fiow of current to the motor field andhaving a lVhen the movable tric part which is movable in one directionto decrease the strength of the current flowing through said motorfield, and a switch separate from said controller which isactuated bysaid movable part of the controller at an intermediate portion of itspath of movement in a direction to decrease the field current, and whichconnects the coils of the 5. The combination with a source of electricpower and an electric motor having a field winding consisting of aplurality of coils, of a controller for regulating the How of current tothe motor field, and a snap switch separate from said controller andactuated by the controller at an intermediate portion of its path ofmovement for connectmg the field coils in series and in parallel.

6. The combination with a source of electric power and an electric motorhaving a field winding comprising a plurality of coils, of a motorcontroller for regulatin the flow of current in the motor fieldan havinga movable part, of a switch for conmeeting said fieldcoils either inseries or in parallel and arranged in a position to be engaged by saidmovable part as the same moves past said switch, said switch comprisinga movable switch member, a switch actuating member adaptedto be engagedby said movable part, and a connection between said switch actuatingmember and said movable member for causing said movable switch member tobe quickly'moved from-one position to another after said switchactuating member has moved through a predetermined distance.

7. The combination with a source of electric power and an electric motorhaving a field Winding consisting of a plurality of coils and anarmature, of a controller for regulating the supply of current to saidarmature and said field coils, and a switch actuated by said controllerwhen starting the motor for connecting the field coils in series afterthe supply of current to the armature has been brought to its maximumand before the supply of current to the field coils has been decreased.

8. The combination with a source of elecpower and an electric motorhaving a field winding consisting of a plurality of coils and anarmature, of acontroller for regulating the supply of current to saidarmature' and said field coils, said controller having resistancedevices adapted to be inserted -into the armature and field circuits,and a switch actuated by said controller when starting the motor toconnect the field coils in series after the resistance has been cut outof the armature circuit and before the reisistance has been insertedinto the field circuit.

Witness my hand, this 20th day of September, 1916.

' FREDERICK G. PECK. Witnesses:

FRANK J. LITTLE, JAMES B. WILSON.

